Dec 6, Reuters - The following is a summary of recent studies on COVID 19. They have research that warrants further study to corroborate the findings and has yet to be certified by peer review.
Re-infection risk may be higher with Omicron variant.
The surviving survivors of previous infection with the virus that causes COVID 19 -- 19 -- SARS-CoV -- 2 may be at higher risk for re-infection with the Omicron variant than with earlier versions of the virus, according to preliminary findings. In South Africa, where Omicron was first reported, researchers looked at data on nearly 2.8 million infections and found that the risk of a first infection increased when the earlier Beta and Delta variants spread during the epidemic's second and third waves, while the risk of a re-infection was low and did not change. But last month, as Omicron spread, daily numbers of re-infections spiked, according to the researchers on Thursday on the website medRxiv https: www.medrxiv. 11.21266068 v 2 ahead of peer review. They said that survivors' risk for re-infection may be rising faster than an average person's risk for a first infection. SARS-CoV-2 infections are usually diagnosed without genetic sequencing to confirm the responsible variant, so this study cannot prove that Omicron is better able to evade the immune defenses put up by the body in response to a previous infection. It doesn't prove anything about defenses generated by vaccination. The timing of the increase in re-infections strongly suggests that the researchers believe that they are driven by the emergence of the Omicron variant. A booster shot of Pfizer BioNTech COVID 19 vaccine appears to provide strong protection, at least in the short term, according to Israel. The data showed that the odds of testing positive for the coronavirus were much lower in adults who received a third dose of the vaccine than in people who received their second dose more than five months ago. More than 306,000 adults were treated for PCR tests after the Pfizer BioNTech booster dose became widely available, according to researchers with Maccabi Health Services. About half of the tests were done in people who had received a booster and half in people who had received only the standard two doses, with at least five months since the second dose. The researchers reported last week in the journal JAMA Internal Medicine that 1.8% of tests were positive in the booster group, compared to 6.6% among those with only two doses. After taking into account the risk factors, they estimated that the third shot was associated with an 86% reduction in the odds of testing positive for the virus, which was associated with an increase in the odds of testing positive for the virus between four and nine weeks after receipt. The researchers compared subsets of closely matched recipients of two or three doses to determine the results. The waning of protection seems to be counteracted by a third dose in the short-term, but longer monitoring is necessary to see how long the protection will last, the researchers said.
The few pediatric recipients of COVID-19 vaccines who develop a heart muscle inflammation known as myocarditis are likely to have mild symptoms that improve rapidly, according to a report published on Monday in the American Heart Association AHA journal Circulation : www.ahajournals. The rare side effect has been reported most often among adolescent and young adult males. The data was collected from 26 children's hospitals across the United States and Canada, focusing on 49 patients ages 12 to 20 who had been hospitalized for confirmed myocarditis within a month of receiving the vaccine, and 91 with probable myocarditis. Most of the respondents were male, 66% were white, and the average age was about 16. While 19% required intensive care, no one died. Half of the patients were sent home within two days. While COVID 19 vaccine-related myocarditis is usually mild and usually resolves quickly, the condition is still a cause of great concern, and it is not clear how patients will do over the long term, the researchers said. They concluded that its risk must be balanced against critical illness and cardiovascular involvement associated with COVID - 19. AHA President Dr. Donald Lloyd-Jones, who wasn't involved in the study, said in a press statement that the benefits of COVID-19 vaccination far exceed the rare risks of adverse events, including myocarditis.